2G Squeak under deaceleration

[Altoids94]

Having a hard time pinpointing where the noise is coming from but it sounds like it's coming from the engine bay. The noise almost sounds like belt squeal (like a rubber on metal contact) but only occurs under deceleration when the engine is bucking going into an engine brake. The squeaking will last longer if I let off in first or second when the engine has more movement. If I ease off the throttle to minimize loading the engine quickly into deceleration the noise will not occur or only slightly. Clutching in will cause the noise to go away immediately so I am thinking it must be directly related to the engine movement. The noise does not occur when any amount of throttle is applied.

Any ideas? Belts are tensioned and I just replaced all of the motor mounts which I initially thought was causing the issues from excessive movement in the mounts.

 

[luv2rallye]

Have you checked the harmonic balancer (aka crank pulley) for separation of it's two halves? Some strange noises/things can happen.
http://www.dsmtuners.com/threads/when-to-replace-your-crank-pulley-harmonic-balancer.169254/